To be fair, not ALL thongs are uncomfortable. Some are genuinely annoying, but others you don't even feel. There are all kinds of different styles to choose from. I used to sell underwear at Victoria's Secret, so trust me. xD
If you are wanting to wear a thong to get rid of panty lines, it's a very good idea. Some fabrics which things like yoga pants and certain skirts are made of show panty lines terribly. A thong will be much more discreet. If you want to wear a thong to look sexier...you should wait a few more years. It's frequently not a very good feeling to be leered at by guys who think you are advertising more than you probably want to.
You really can't go wrong with a lovely pair of thin, line-free bikini underwear. If you get the right cut and fabric, they won't show through clothes either. I swore by thongs for years, but over the past few years I have realized that I generally prefer a good bikini or hiphugger brief. Comfy, practical...and they come in SUCH a variety of pretty colors and patterns!